auxiliaries

a.他能讲有趣的故事（能力）。B.他有时还真会讲些有趣的故事。
I can do it. 我可能/可以/能/愿意办这件事。
Could (1) To express the past ability When he was a child he could climb trees in the forest. He read the passage but he couldn’t understand it. She could / was able to write poems when she was nine. No one could / was able to answer the question. could He ____ / was able to swim halfway before he collapsed. He got so drunk that he couldn’t / wasn’t able to find the front door. He said he had lost his passport and hadn’t been able to leave the country. (2) To express past permission Until recently no visitors could remain in the hospital after eight p.m. The castle could be visited in those days.
3. Must (1)To express obligation (必须、必要） 必须、 必须 必要） We must hand in our exercise-books today. Must we hand in our exercise-books today? Yes, you must. _____________ No, you mustn’t. No, you needn’t. / don’t have to. (2) To express a sure guess It must be eleven o’clock now. He must be mad. You must be joking. You must be careful. / You must be careless. (3) To express inevitability All men must die. Bad seeds must bring bad crops. (善有善报，恶有恶报）
You can be very annoying. He can be very tactless sometimes. Scotland can be very cold. (3) To express permission You can park here. Can I use your dictionary? You can’t smoke here. (4)To express willingness/request Can you pass me the salt? Can you help me? Ambiguity: He can tell interesting stories.
We shall be going to Paris by plane next week. Will you spend your summer holidays abroad? Will you be spending your summer holidays abroad? Modal auxiliaries: Can, could, may, might, must, ought to, need, dare, should, would II. Some uses of Modal auxiliaries 1. can, could Can: (1) To express the present and future ability Liu Xiang can run very fast. Can you speak English? I can’t pay you today. Will you wait till tomorrow? I can give you an answetive verbs may active or passive. a. The rules of English permit transitive verbs to be active or passive. b. It’s possible that transitive verbs are active or passive. Might (1) As the past form of “may” expressing permission and possibility I asked if I might go home half an hour earlier today.(许可） I thought you might stay with us.（许可/ 可能） He said he might be late.（可能） He told me she might go to Hainan this winter.（可能） (2) To substitute for “may” to express a mild tone Might (May) I use your phone? He might (may) have gone home. They might (may) not believe your story.
No one can do it. → No one is able to do it. Can you come tonight? → Will you be able to come tonight? Our baby can walk in a few weeks. → Our baby will be able to walk in a few weeks. John has been able to swim for years. Since his accident he hasn’t been able to walk properly. → be able to: 现在的能力 Can → shall / will be able to ：将来的能力 → have been able to：延续至今的能力 (2) To express possibility Can it be true? That can’t be Mary----She has gone to Shanghai. She can’t be telling the truth.
(3) To express possibility Could it be true? A: Who is knocking at the door? B: It could be Mary. Could he be waiting for us at the station? Could can be replaced with can, but could is more polite. 2. may, might May: (1) To express permission May I come in? Yes, you may. / Yes, come in, please. No, you may not. / mustn’t. May I dance with you? Yes, of course. / Yes, with pleasure. I’d like to, but …
(4) Must ---- have to You must read the novel. It’s really interesting. She felt ill and had to leave early. must：表说话人的主观看法，认为有必要有义务去做 ：表说话人的主观看法， 某事 have to:表客观需要去做某事 表客观需要去做某事 4. Need (1) Used in negative or interrogative sentences _______________ He need be told. He needn’t be told. He doesn’t need to be told. “ He needn’t be told.” Because it is unnecessary to tell him, for there is nothing to do with him. “He doesn’t need to be told.” Because he has already known it.
(2) Need I come tonight? _______ Yes, you need. →you must. No, you needn’t. (3) didn’t need to do sth. （不必做某事，实际上也没有做） needn’t have done sth.(不必做某事，实际上却做了） You didn’t need to hurry. You needn’t have hurried. 5. Dare (1) Used in interrogative, negative sentences or if-clauses I dare not go there If you dare speak to me like that again, you shall be sorry . Dare you ask him? (2) Dare say, dare to say There is something wrong with the machine, I dare say. I dare say you are right. Do you dare to say that you didn’t do it?
Auxiliaries I. Classification of auxiliaries 1. Primary auxiliaries 2. Modal auxiliaries Primary auxiliaries be, have, do He is writing a letter. Have you had your dinner? They do not agree with what you say. Do you have anything special to do this afternoon? shall, will: primary auxiliary or modal auxiliary? When and where shall we meet next time? It will rain tomorrow. he shall do it as I say. Whatever you may say, he will do it as I say.